Commitments And Contingent Liabilities (Environmental Matters) (Detail) $ in Millions	Dec. 31, 2020 USD ($) Plant mi	Dec. 31, 2019 USD ($)
Site Contingency [Line Items]
Percentage of residential gas supply permitted to be recovered in gas hedging by BPU	80.00%
Number of miles related to the Passaic River constituting a facility as determined by the US Environmental Protection Agency | mi	17
Number of legal entities contacted by EPA in conjunction with Newark Bay study area contamination	11
Accrued environmental costs	$ 286	$ 349
Public Service Electric and Gas Company
Site Contingency [Line Items]
Accrued environmental costs	236	294
Regulatory Assets	4,241	$ 4,028
MGP Remediation Site Contingency [Member] | Public Service Electric and Gas Company
Site Contingency [Line Items]
Remediation liability recorded as other current liabilities	89
Remediation liability recorded as environmental costs in noncurrent liabilities	231
Regulatory Assets	$ 320
PSE&G's Former MGP Sites [Member]
Site Contingency [Line Items]
Number of MGP sites identified by registrant and the NJDEP requiring some level of remedial action	38
Passaic River Site Contingency [Member]
Site Contingency [Line Items]
Estimated Cleanup Costs EPA Preferred Method	$ 2,300
Aggregate number of PRPs directed by the NJDEP to arrange for natural resource damage assessment and interim compensatory restoration along the lower Passaic River	56
Accrual for Environmental Loss Contingencies	$ 65
Passaic River Site Contingency [Member] | Public Service Electric and Gas Company
Site Contingency [Line Items]
Number of former generating electric station | Plant	1
Accrual for Environmental Loss Contingencies	$ 52
Passaic River Site Contingency [Member] | PSEG Power LLC
Site Contingency [Line Items]
Accrual for Environmental Loss Contingencies	13
Minimum | MGP Remediation Site Contingency [Member] | Public Service Electric and Gas Company
Site Contingency [Line Items]
Loss Contingency, Estimate of Possible Loss	320
Accrual for Environmental Loss Contingencies	320
Maximum [Member] | MGP Remediation Site Contingency [Member] | Public Service Electric and Gas Company
Site Contingency [Line Items]
Loss Contingency, Estimate of Possible Loss	$ 358